schroder



Feb. 20, 19230 L446A35 F. SCHRCDER MANUFACTURE OF CONCRETE ARTICLES Filed July 22, 1920 Patented 219, i923.

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FERDINAND SCHRflDER, F BERLIN, GERMANY, ASSIG-NOR TO INTERNATIONALE SIEG-WARTBALKEN-GESELLSCHAFT, 0F LUZERN, SWITZERLAND.

MANUFACTURE 0F CONCRETE ARTICLES.

a ncaudn filed July 22, 1920. Serial no. 393,299.

(GRANTED UNDER THE PRQVINEUHS 9F THE ACT (PF MARSH 3, 1921, 41 STAT. L., 1313.)

To all whom it may concern:

Be it known that I, Fnnnmimn taonnonnr, merchant, a citizen of the German Republic, and residing at Berlin, (ilermany, have in- .5 vented certain new and useful Improvements in the Manufacture of Concrete Articles (for which I have filed applications for patents in the following countries: (12er many March 29, 1919, Austria November 5,

in 1919, Hungary November 21, 1919, Poland January 2, 1920, Czecho-Slovakia December 15, 1919, Great Britain December 6, 1919, France December 1, 1919, Italy November 12, 1919, and Finland December l5,

15 1919), of which the following is a specification.

This invention relates to a method of making articles of pebble or gravel concrete, having inserted patches or places formed of aszo bestos cement concrete, which is capable of being worked.

Concrete is now largely used for the male ing of many articles which were formerly made of wood, such for instance, as railway sleepers, beams, columns or uprights, masts and the like. As pebble concrete, after hardening and setting or binding, is not capable of being worked, it is necessary to form those parts of the pebble concrete articles,

which, as in the case for instance, of railway sleepers are intended to afterwards receive screw bolts, nails or the like for the pun pose of fastening the rails, of material adapted to be operated on, and for this purpose asbestos cement concrete is preferably selectedby reason of its capacity of being easily worked upon and its imperishable qualities, and also because it comb nes thoroughly with the pebble concrete without the 40 formation of intervals, crevices, cracks or the like at the joints.

In the accompanying drawing Fig. 1 is a sectional view of a body of gravel and cement provided with an ins ertion of asbestos cement, in accordance with my invention.

Fig. 2 is a plan of the same.

In the drawing, the body of gravel and cement is indicated at a, the insertion of asbestos cement is indicated at Z), and the woven wire is indicated at c.

In order that in the mutual binding or set ting of the different kinds of concrete, these should not become mingled with one another, and gravel particles from the gravel or pebble concrete should not pass over into the adjacent asbestos cement concrete, which would deleteriously afi'ect the capability of the latter to be worked upon, in filling in the two different kinds of concrete into the mould, sheet metal shields or sliding pieces have hitherto been employed for separating them, which shields were withdrawn when the mixtures had been completely introduced and smoothed. If this withdrawal occurs too soon, the penetration of particles of gravel or pebbles into the asbestos cement concrete cannot be prevented. If the slides or shields are withdrawn too late, the homo-v genco'us connection of the different mixtures when setting is affected, and later on crevices or cracks are easily formed, or the inserted asbestos concrete portions gradually become entirely loosened. Further, the slides can only be employed where it was a question of straight or only simple curved bordering surfaces or faces.

Now by this invention, sieves or cloths of thin wire, sheet metal, asbestos yarn, or other suitable material may be employed for obtaining a certain separation between the two different kinds of concrete during the simultaneous ramming in, which'is cf fected by hand or mechanically, or in the common filling or shaking in of the two different kinds of concrete, and these dividing substances remain in the article tobe made, even after its completion, but have such a width of mesh, that while they prevent the passage of pebbles, or gravel partieles from the gravel or pebble concrete into the asbestos cement concrete with certainty they do not impede the common homogeneous binding together of the two different kinds of concrete at the contact faces or places. v

As the sieves or cloths remain in the article even when finished, and therefore do not need to be withdrawn before the setting, they may be of any suitable form and hence the formation of the asbestos cement concrete parts which are to be embedded in the pebble concrete is not restricted to the narrow limits which naturally result where slides or shields are employed, which have to be withdrawn before the setting of the concrete.

According to the process forming the object of the present invention, there are thus obtained articles; of pebble concrete. haying;

inserted places of asbestos cement concrete, in Which both klnds of concrete are combined i u-lly hoinoge11eously to a :monolithic unity, and in n hich the asbestos cement concrete places can be operated on in any suitable Way. They may be planed, cut, bored,

and nails and screws can also be driven into them, so that other constructional parts may be thereby connected with them securely and permanently.

Playing now; described myinvention, What I desire, toisecure by. (a :patent of :the United States is I 1. The method. of: inakingiconcretearticles composed ofmore thanone-character of con crete,- \vhich consistsin embeddinga screen in the article' during the simultaneous rainming in at the boiinding line between thevarious kinds of concrete; to prevent. theln testimony,whereofl'haveaffiiied my signature in presence of two-Witnesses.

FERDINAND. SGHRGDER;

Witnesses CHE. OURTHS, i w hinwin' Losninn. 

